- Preparation, photophysical, electrochemical, and ion-binding properties of Ru(II) polypyridyl complexes containing a crown ether unit
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Two polypyridyl ligands, 4'-(4,5-diazafluoren-9-ylimino)benzo-15-crown-5 (L1) and 4'-(4,5-diazafluoren-9-ylimino)benzo-12-crown-4 (L 2), and their Ru(II) complexes [(bpy)2RuL](PF 6)2 and [(bpy)2RuL2](PF 6)2, respectively, have been synthesized and characterized. The two complexes display metal-to-ligand charge transfer absorptions at around 444 nm in CH3CN solution at r. t. and emission at around 573 nm in an EtOH-MeOH (4:1, v/v) glassy matrix at 77 K. Electrochemical studies of the complexes show one Ru(II)-centered oxidation at around 1.33 V and three ligandcentered reductions. The binding ability of the complexes with Na+ and Li+ has been investigated by UV/Vis absorption and emission spectroscopy and electrochemical titrations. Addition of Na+ and Li+ to solutions of the complexes results in a progressive quenching of the emission, a hyperchromic effect of the UV/Vis absorption, and a progressive cathodal shift of the Ru(II)-centered E 1/2 potential. The stability constants for the stoichiometric 1:1 ratio of the complexes and the cations have been obtained by UV/Vis absorption titration.
- Cheng, Feixiang,Tang, Ning,Chen, Jishu,Wang, Fan,Chen, Longhai
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- ESI-MS Detection of Very Weak π-Stacking Interactions in the Mixed-Ligand Sandwich Complexes Formed by Substituted Benzo-Crown Ethers and Metal Cations
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The stability of the mixed-ligand complex formed by amino-benzo-15-crown-5 and nitro-benzo-15-crown-5, with a metal cation, [NH2B15C5 + NO2B15C5 + K]+, was found to be enhanced by π-stacking interactions. This conclusion was deduced by comparison of the abundance of the mixed-ligand complex with the abundances of homo-ligand complexes ([(NH2B15C5)2 + K]+, [(NO2B15C5)2 + K]+), as well as with those of 1:1 complexes ([NH2B15C5 + K]+, [NO2B15C5 + K]+). Some solvents and some metal cations with large radii were also found to prevent the existence of π-stacking interactions.
- Franski, Rafal,Gierczyk, Blazej
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- Chalcogen Bond Mediated Enhancement of Cooperative Ion-Pair Recognition
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A series of heteroditopic receptors containing halogen bond (XB) and unprecedented chalcogen bond (ChB) donors integrated into a 3,5-bis-triazole pyridine structure covalently linked to benzo-15-crown-5 ether motifs exhibit remarkable cooperative recognition of halide anions. Multi-nuclear 1H, 13C, 125Te and 19F NMR, ion pair binding investigations reveal sodium cation–benzo-crown ether binding dramatically enhances the recognition of bromide and iodide halide anions, with the chalcogen bonding heteroditopic receptor notably displaying the largest enhancement of halide binding strength of over two hundred-fold, in comparison to the halogen bonding and hydrogen bonding heteroditopic receptor analogues. DFT calculations suggest crown ether sodium cation complexation induces a polarisation of the sigma hole of ChB and XB heteroditopic receptor donors as a significant contribution to the origin of the unique cooperativity exhibited by these systems.
- Bunchuay, Thanthapatra,Docker, Andrew,Eiamprasert, Utt,Surawatanawong, Panida,Brown, Asha,Beer, Paul D.
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- Direct nitration method of electron-enriched aromatic hydrocarbons
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The invention discloses a direct nitration method of electron-enriched aromatic hydrocarbons, and belongs to the field of organic synthesis. The direct nitration method is a novel green free radical nitration method; aromatic hydrocarbons are taken as raw materials, acetonitrile, dichloromethane, chloroform, or acetone is taken as a reaction solvent, at room temperature conditions, the raw materials and green nitration reagent tert-butyl nitrite (TBN) are subjected to free radical nitration so as to obtain nitro-aromatic compounds. According to the direct nitration method, no metal is adoptedin reaction, tert-butyl nitrite is directly adopted in nitration reaction. Electron-donating groups such as OMe are introduced, the electron density of aromatic compounds is increased, the nitration reaction possibility is increased. The using amount of tert-butyl nitrite is reduced; only a product and tert-butyl alcohol are generated, environment pollution is reduced. The direct nitration methodis promising in application prospect in the field of nitro-aromatic compound synthesis, green nitration is realized, and a novel idea is provided for large-scale industrialized nitro-aromatic compoundproduction.
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Paragraph 0102-0104
(2018/10/02)
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- Production of macrocyclic polyether benzo-15-crown-5 and its functional derivatives
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Study of interaction between catechol and tetraethylene glycol dichloride in the n-butanol media, resulting with benzo-15-crown-5 production. Production of nitro- and amino-derivatives of benzo-15-crown-5. Determination of their thermogravimetric characteristics.
- Glushko, Valentina N.,Sadovskaya, Natalya Yu.,Kozhuhov, Vadim I.,Blokhina, Lidiya I.,Antropova, Irina A.,Petina, Ekaterina S.,Retiviov, Vasiliy M.,Melnikova, Ekaterina Yu.
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p. 1689 - 1697
(2017/10/27)
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- Synthesis and properties of macroheterocyclic azomethines based on 4-aminobenzo-15-crown-5
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A number of new stable azomethine crown ether derivatives have been synthesized by condensation of 4-aminobenzo-15-crown-5 with aromatic aldehydes. Complexation of the products with transition metal cations (Cu2+, Zn2+, Fe3+, Co3+, Ni3+) has been studied by spectrophotometry.
- Sadovskaya, N. Yu.,Glushko,Retivov,Belus',Grokhovskii
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p. 2771 - 2777
(2016/02/18)
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- Supramolecular assembly of isocyanorhodium(i) complexes: An interplay of rhodium(i)···rhodium(i) interactions, hydrophobic-hydrophobic interactions, and host-guest chemistry
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A series of tetrakis(isocyano)rhodium(I) complexes with different chain lengths of alkyl substituents has been found to exhibit a strong tendency toward solution state aggregation upon altering the concentration, temperature and solvent composition. Temperature- and solvent-dependent UV-vis absorption studies have been performed, and the data have been analyzed using the aggregation model to elucidate the growth mechanism. The aggregation is found to involve extensive Rh(I)···Rh(I) interactions that are synergistically assisted by hydrophobic-hydrophobic interactions to give a rainbow array of solution aggregate colors. It is noted that the presence of three long alkyl substituents is crucial for the observed cooperativity in the aggregation. Molecular assemblies in the form of nanoplates and nanovesicles have been observed in the hexane-dichloromethane solvent mixtures, arising from the different formation mechanisms based on the alkyl chain length of the complexes. Benzo-15-crown-5 moieties have been incorporated for selective potassium ion binding to induce dimer formation and drastic color changes, rendering the system as potential colorimetric and luminescent cation sensors and as building blocks for ion-controlled supramolecular assembly.
- Chan, Alan Kwun-Wa,Wong, Keith Man-Chung,Yam, Vivian Wing-Wah
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p. 6920 - 6931
(2015/06/16)
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- Novel benzo-15-crown-5/C60 dyads with different chains: Synthesis and complexation properties
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Using benzo-15-crown-5 derivatives as starting materials, two novel benzo-15-crown-5/C60 dyads with different linking chains were designed and synthesized in good yields by 1,3-dipolar cycloaddition of azomethine ylide generated in situ from al
- Hong, Biqiong,Yang, Fafu,Ye, Jinqi,Guo, Hongyu,Yan, Xiaoyun
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- Self-assembled dimerization of bis(crown ether)-2,2′-bibenzimidazoles
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Bis(crown ether)-2,2′-bibenzimidazole 1 and its 1-substituted derivatives were synthesized as new self-assembled motifs. UV-vis and 1HNMR titration experiments of 1 with potassium ions in a mixture of chloroform and methanol (1:1) were carried out. The stoichiometries and curve fitting analysis showed that a 2:2 complex of 1 with potassium ions was formed in a face-to-face fashion. 1-Monosubstituted bis(crown ether)-2,2′- bibenzimidazole 6a having a (dodecylaminocarbonyl)methyl group also gave a 2:2 complex with potassium ions. Structural analysis of the 2:2 complex of 6a with potassium ions was performed using various two-dimensional NMR techniques. Results suggested that, of eight or more possible conformational isomers, the one having the two substituent groups diagonally opposite each other was predominantly formed. Reversible association and dissociation of the 2:2 complex was observed after adding potassium ions and then removing them with an 18-crown-6-ether.
- Satake, Akiharu,Tanaka, Kazuo,Asakura, Hiroki,Okano, Masahiro,Hashimoto, Tsutsumu,Matsuura, You,Inaba, Yusuke,Oda, Tetsuhisa,Hirota, Shun,Koshino, Hiroyuki
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- Nitro derivatives of N-alkylbenzoaza-15-crown-5: Synthesis, structures, and complexation with metal and ammonium cations
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A number of N-alkylnitrobenzoaza-15-crown-5 with the macrocycle N atom conjugated with the benzene ring were obtained. The structural and complexing properties of these compounds were compared with those of model nitrobenzo- and N-(4-nitrophenyl)aza-15-cr
- Dmitrieva,Churakova,Kurchavov,Vedernikov,Kuz'Mina,Freidzon, A. Ya.,Bagatur'Yants,Strelenko, Yu. A.,Howard,Gromov
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experimental part
p. 1192 - 1206
(2011/02/23)
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- Bimodal fluorescence signaling based on control of the excited-state conformational twisting and the ground-state protonation processes
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Amino-based fluoroionophores 1 and 2 can selectively sense alkaline earth metal ions in MeCN under both neutral and acidic conditions by different signaling mechanisms. The fluoroionophoric behavior for the neutral probes is characterized by an 'off-on' photoinduced electron transfer (PET)-like fluorescence intensity response due to a switching from a twisted internal charge transfer (TICT) to a planar internal charge transfer (PICT) state. For the protonated probes (i.e., 1/H+ and 2/H+), the fluorescing species is the localized stilbene fluorophores, but dual fluorescence is induced upon metal-ion recognition through a deprotonation process.
- Yang, Jye-Shane,Hwang, Chung-Yu,Chen, Mon-Yao
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p. 3097 - 3102
(2008/02/02)
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- Nitration of benzo crown ethers with potassium nitrate in polyphosphoric acid
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A general method for the nitration of benzo crown ethers with potassium nitrate in polyphosphoric acid has been developed. Mono- and dinitro derivatives of benzo-12-crown-4, benzo-15-crown-5, dibenzo-18-crown-6, and dibenzo-24-crown-8 have been prepared. The role of complex formation in the regioselective tendency for the nitration of dibenzo-18-crown-6 has been demonstrated.
- Grebenyuk,Andreev,Stempnevskaya,Levkovich,Tashmukhamedova
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p. 1449 - 1456
(2007/10/03)
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- Highly preorganized bis(benzocrown ether)s for the binding of metal ions
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Several bis(crown ethers)s consisting of benzo-12-crown-4, benzo-15-crown-5, and benzo-18-crown-6, were prepared and their complexation properties with Na+ and K+ were determined by the liquid-liquid extraction method. The remarkable 'biscrown effect' was observed in the extractions of both Na+ and K+ using bis(benzo-12-crown-4) and bis(benzo-15-crown-5). Unsymmetrical bis(crown ether)s also exhibit much higher extractabilities of both Na+ and K+ than the corresponding mono(benzocrown ether)s.
- Jeong, Kyu-Sung,Pyun, Seung Yup
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p. 7041 - 7044
(2007/10/02)
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- Benzocrown Derivatives as Ionophores for Alkali Cations, III.- Synthesis of Ring-Cleaved Analogues of Benzocrown Ethers.- A Novel Method for Building Up Crown Ether Rings
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Several ring-cleaved analogues (9, 11a,b) of bis(benzo-15-crown-5)-urethanes (1a,b) were prepared to study the change of complexation by electroanalytical methods.The syntheses of the title compounds (9, 11a,b) were accomplished in two ways: starting from 4-nitroveratrole (2) via intermediates 3-8 to give compound 9 and by alkaline hydrolytic cleavage of 4-nitrobenzocrown ethers (10a,b), then by subsequent steps yielding 11a,b.
- Toeke, Laszlo,Bitter, Istvan,Agai, Bela,Hell, Zoltan,Lindner, Ernoe,et. al.
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p. 761 - 764
(2007/10/02)
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- NUCLEOPHILIC RING CLEAVAGE OF CROWN ETHERS, NOVEL METHOD FOR BUILDING UP CROWN ETHER RINGS
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The crown ether rings in 4-nitrobenzo-15-crown-5 and -18-crown-6 are cleaved by aqueous alkali affording long chain substituted pyrocatechols which proved to be good starting material for constructing crown ether rings other than the original one.
- Agai, Bela,Bitter, Istvan,Hell, Zoltan,Szoelloesy, Aron,Toeke, Laszlo
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p. 2705 - 2708
(2007/10/02)
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- Potentiometric Digoxin Antibody Measurements with Antigen-Ionophore Based Membrane Electrodes
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We describe and illustrate a technique, potentiometric ionophore-modulation immunoassay (PIMIA), for the measurement of antibodies with conjugate based membrane electrodes.Fundamental operating variables for the technique are examined and demonstrated for the case of antibodies to the cardiac drug digoxin.Detection limits in the μg/mL range, with high selectivity over other antibodies and proteins, are readily attained.Through a competitive binding approach, the selective measurement of digoxin itself is also shown to be possible with this technique.
- Keating, M. Y.,Rechnitz, G. A.
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p. 801 - 806
(2007/10/02)
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- Double Ionophore with Dihydrotetraazaannulene- and Crownether-Function
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Benzocrown-5 (1) was converted in four steps into the 4-amino-5-nitro-derivative 5, which, after reduction to the diamine 6, cyclocondenses with 3-ethoxy-2-isopropylacrolein.The resulting trimacrocyclic ligand 7 chelates nickel(II) and cobalt(II) ions and, additionally, potassium and sodium ions, thus being a double ionophore.
- Kruse, Rolf,Breitmaier, Eberhard
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p. 832 - 836
(2007/10/02)
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